An apparatus of this kind is known in which the printed circuit board to be mounted is received in a first carrier and the components are removed from a magazine by means of a second carrier and placed on the printed circuit board. The second carrier includes a mounting tool arranged on a mounting head which can be displaced by hand in a horizontal cross guide parallel to the plane of the printed circuit board and in a vertical guide transverse to the plane of the printed circuit board, namely vertically, in order to be able to remove the respective component from the magazine and to place it on the printed circuit board. The mounting tool can be a suction needle connected to a vacuum source at the tip of which the components can be grasped by means of suction air. The suction needle can, when affixing the component carried by it on the printed circuit board, be displaced a short distance in its longitudinal direction and thereby operate a switch which switches the vacuum source off so that the component is released. In reverse the suction needle can, when the vacuum source is switched off, be placed on the component on the printed circuit board and be pressed on it whereby the micro-switch is actuated again and the vacuum source is switched on. By this means the component can be removed from the printed circuit board by the needle when it is free of its solder. When mounting a component on the printed circuit board the operator places the ball of the thumb of his hand holding the mounting head on a support provided on the apparatus. The operating hand therefore tends to carry out a curved movement when the mounting head is being lowered. This curved movement results in a slight lateral displacement of the component on the printed circuit board which is undesired in the last phase of lowering the mounting head, that is to say when the respective component has already reached the printed circuit board but the mounting head is lowered still further. With the high precision that is required today, in particular for placing SMD (small mounted device) components this can result in mis-wiring.
Lateral displacement of the component after being placed on the printed circuit board is also always possible owing to the more or less great instability of the operator's and mentioned above, in particular in the case of inexperienced operators. It requires considerable attention and effort to hold the mounting head after the component has been placed on the printed circuit board, particularly if this holding requires a long time, which often occurs when repairing printed circuit boards.
A further problem in an apparatus of the kind described in the introduction, in which the carrier is subjected to biassing directed upward which when released by the operator's hand takes it back to its upper starting position, consists in that the operator's hand is bound to the carrier while the component is being pressed on to the printed circuit board. This is true of both mounting operations and of repair work on mounted printed circuit boards in which defective components are to be removed or unsoldered from the printed circuit board and replaced by good components. Because the operator's hand is bound to the carrier displaceable transverse to the plane of the printed circuit board the so-called work of the operator can only be carried out with difficulty.